The 209-3-1REC4-66-4-8-50 is a three-pole E-frame hydraulic magnetic circuit protector from the AIRPAX 209 Series, designed for accurate and reliable circuit protection in compact multi-pole configurations. This unit features front-connected screw terminals (10-32 or 1/4-20), a delay 66 characteristic for motor load protection, and is rated for operation up to 100 amperes at 240Vac or 125Vdc. The three-pole common-trip construction ensures that an overload in any pole opens all poles simultaneously, with externally ganged handles for coordinated actuation. The delay 66 characteristic provides long-delay protection with trip times ranging from 70 to 800 seconds at 125% rated current down to 0.013 to 3 seconds at 1000% rated current. This circuit protector is ideal for branch circuit applications including EDP systems, air conditioners, panel boards, and lighting controls where reliable multi-pole protection is required.